However, there is one thing that should be fixed and I'll show you how! The problem: the hair.
In GoldSource you can't use alpha transparency, but that doesn't mean you can't use any other kind of transparency! You can achieve transparency using the color palette!
I'll be using Photoshop. Open the face_diffuse.bmp. In the menu select Image >> Mode >> Color Table.
Select the bottom right square (a) and set it's color (b) to something that's not on the palette. I'll be using 255,0,255 (also known as pink) because it is one of the most common colors used for transparency. Set your primary color the same as the color you used in the palette.
Using the magic wand tool, contigiuous mode on and a tolerance of 1, I made this selection:
Paint this selection with the color you set in the Color Table.
Save the texture and open the model. Import the texture and check the Transparent tickbox. Now if everything went good it should look like this:
Before and after:
Save the model, get it in-game and enjoy transparent hair!